ZURICH Swiss inspections group SGS denied on Thursday any responsibility for security at the site where radioactive material used to test pipes at an oil field in southern Iraq disappeared last year.

It also said the radioactive content was most likely very weak.

"The site where these operations are conducted is fully secured and guarded by security guards under the responsibility of the owner of the site. SGS does not assume any responsibility for the site security and does not control accesses," it said in a statement on Thursday, adding many contractors used the site.

Reuters reported on Wednesday that Iraq was searching for "highly dangerous" radioactive material whose theft last year had raised fears among Iraqi officials that it could be used as a weapon if acquired by Islamic State.

SGS said its Turkish unit had been hired by U.S. group Weatherford to perform the tests, which use what it called a low-level radioactive source.

Radioactive sources used in equipment like this are similar in strength to those used in medical radiography, SGS said.

"At the time of the disappearance of the equipment, the source was close to the end of its useful life," SGS said in a separate statement. "It is therefore safe to affirm that the remaining radioactive content of the source is now very weak."

The equipment and radioactive source are stored in a "secured bunker" provided by Weatherford when not in use, SGS said.

"The disappearance of the equipment occurred while the equipment was stored in the Weatherford bunker," it said, adding the loss was discovered on Nov. 3.

Its Turkish business immediately notified Iraqi authorities and cooperated fully with the investigation, it said.

Weatherford has also said that it was not responsible or liable for the theft. "We do not own, operate or control sources or the bunker where the sources are stored," it said on Wednesday.